JPH02216173A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To improve picture quality by making the gap between a roller and an image carrier greater in a central part and less on both ends and forming the surface of the roller with substance having less surface energy. CONSTITUTION:When toner remaining on a photosensitive body 1 comes to the position of a cleaning device 2, it is scraped away from the photosensitive body by a cleaning blade 3. A magnet roller 4 attracts the toner recovered from the photosensitive body 1 and carries it. The carried toner is stored in the toner pool B of a toner layer thickness regulating roller 5. A part of the toner naps on the surface of the roller 4 to form a magnetic brush, comes to the opposite position to the photosensitive body 1 as the roller 4 rotates, and is cleaned out in sliding fashion. The roller 5 is made of nonmagnetic material, and its surface is coated with fluorine contained resin of 10 to 50mum. The central part of the roller and its both ends have different diameters, and a gap d1 is less than (d). Consequently, toner is prevented from leaking from both ends of the roller 5 to prevent toner soil. An excellent image can thus be obtained.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that utilizes an electrostatic transfer process, such as an electrostatic copying machine or a printer, and particularly to a cleaning device therefor. be.

(Prior art and issues to be solved) A process in which a toner image is electrostatically formed on the surface of a photoreceptor that normally runs in an endless manner, and this toner image is electrostatically transferred to a transfer material, mainly paper. In well-known image forming apparatuses that repeatedly transfer images, it is essential to sufficiently remove residual toner that does not transfer to the transfer material and remains on the photoreceptor each time transfer is performed, in order to obtain high-quality images. As a cleaning means, cleaning blades made of elastic materials such as urethane rubber have been widely used since they have an excellent toner removal function, are small and have a simple structure, and are advantageous in terms of cost. As is known.

However, toner is not the only substance that remains on the surface of the photoreceptor (
There are various types of particles that can adhere to the photoreceptor and cause deterioration of image quality, such as fine paper dust generated from paper, which is the most commonly used transfer material, and corona products caused by high-pressure components in the device. There are foreign substances, etc., which are difficult to sufficiently remove using only a cleaning blade.

Therefore, in order to remove these foreign substances, especially in the case of a device that uses one-component magnetic toner, a magnetic roller is placed in the cleaning device along with a cleaning blade, and the toner collected in the device is attached to the magnetic roller. A method has been proposed in which a magnetic brush is formed in the photoreceptor, the magnetic brush is brought close to the photoreceptor, and the surface of the photoreceptor is rubbed with the magnetic brush to remove the above-mentioned foreign matter.

The above-mentioned means do not have to remove the foreign matter as mentioned above, but instead apply a small amount of toner to the photoreceptor from the formed 81 brush and supply it to the edge of the cleaning blade to exert a lubricating effect. In addition, it applies mechanical stimulation to the toner adhering to the photoconductor surface, weakening the adhesion to the photoconductor, and making it easier for the cleaning blade to remove the toner. Because of these advantages, component (2) magnetic toners, which are usually used to obtain black images, have achieved certain effects.

By the way, recently, in order to obtain color images other than black,
There is an image forming apparatus in which one or several developing units containing color toner are arranged together with a developing unit containing toner for black images, and these developing units are selectively used to obtain multicolor copies. It is gradually being used.

Color toners used in such image forming apparatuses are usually composed of a transparent resin mixed with dyes and pigments, and therefore are non-magnetic toners.

Therefore, when this toner is used in an image forming apparatus that has a cleaning device equipped with a magnetic roller, which is suitable for the one-component magnetic toner described above, the color toner is not attracted to the magnetic roller, and the magnetic brush is removed. Since the formation and the effect thereof cannot be expected, problems inevitably arise in the function of the cleaning device.

In order to match the cleaning action with non-magnetic toner, it is possible to use a cleaning blade as the main component without using a magnetic roller, but even in such a device capable of multicolor copying, it is difficult to obtain a black image using component toner. It goes without saying that it would be disadvantageous to immediately stop using the magnetic roller, taking into consideration the existence of the above-mentioned advantages, since sufficient thrust is often applied.

From this point of view, the present applicant caused a magnetic roller disposed close to the photoconductor to run at low speed in the forward direction of the photoconductor, and at the same time formed a toner reservoir at a suitable location, and stored a considerable amount of toner there. We have proposed a configuration in which the proportion of non-magnetic toner present in the toner forming the magnetic brush in the area facing the photoconductor is made as low and uniform as possible.

FIG. 3 is a schematic view of the essential parts of the cleaning device, with the cleaning device 2 arranged parallel to the photoreceptor 1, which has an axis perpendicular to the plane of the paper and rotates in the six directions of the arrows. , a cleaning blade 3 inside the device. A magnet roller 4 is arranged on the upstream side thereof.

The toner collected in the cleaning device is sequentially guided to the back of the cleaning device as the magnet roller 4 rotates, and after the toner is scraped off by the magnet roller end scraper IO. A large amount of toner can be stored in the space formed by the magnet roller 4, the toner layer thickness regulating roller 5, and the regulating roller scraper 8 that comes into contact with the roller.

With this structure, a large amount of one-component toner is generally stored in the empty space, and even if non-magnetic toner is taken in here, the amount as a whole is unlikely to increase too much. The formation of magnetic brushes on the magnetic rollers and the resulting deterioration of the cleaning action are substantially avoided.

However, in the above-mentioned apparatus, the configuration becomes complicated due to the presence of the regulation scraper 8 and the magnetic roller scraper 1O, and the installation requires precision and reliability, which increases the assembly cost. There were other problems.

If the regulating scraper 8 is removed, the toner adheres to the roller 5 and is conveyed, and is removed by the scraper disposed on the partition handler 9, making it difficult to form the toner pool D.

The present invention has been made in view of the above-mentioned situation, and is an image forming apparatus that uses a cleaning device equipped with a magnetic roller for cleaning and uses both magnetic toner and non-magnetic toner. It is an object of the present invention to provide a leaning device that can maintain stable and good leaning function at all times.

(2) Structure of the invention (technical means for solving the problem and their effects) In order to achieve the above object, the present invention comprises an image carrier and a cleaning device disposed close to the image carrier and moving relative to the image carrier. The cleaning device includes a cleaning blade and a magnet roller upstream thereof that forms a toner layer of collected toner and performs cleaning, and a roller that regulates the thickness of the toner layer and an image roller. The roller is characterized in that the distance from the carrier is large at the center of the roller and small at both ends, and the surface of the roller is formed of a material with low surface energy.

With this configuration, it is possible to stabilize the thickness of the toner layer formed on the magnet roller, and to prevent the toner from escaping and scattering from the cleaning device.

(Description of Embodiments) FIG. 1 is a side sectional view of a cleaning device showing an embodiment of the present invention, in which a one-component magnetic toner is also used as the developer, extending in a direction perpendicular to the plane of the paper, The photoreceptor 1 rotates in the direction of arrow A, and the photoreceptor 1 is an amorphous silicon photoreceptor, and a cleaning device 2 is arranged close to and parallel to the photoreceptor 1.

At a transfer position (not shown), when the residual toner remaining on the photoreceptor 1 without being transferred to the transfer material reaches the position of the cleaning device 2 as the photoreceptor 1 rotates, the cleaning blade 3 attached to the cleaning device Residual toner is scraped off the photoreceptor by one edge of the photoreceptor that contacts the photoreceptor.

A magnet roller 4 that rotates in the direction of the arrow shown in the figure is disposed on the upstream side of the cleaning blade 3 when viewed in the traveling direction of the photoreceptor 1, and is spaced a small distance 2 from the photoreceptor 1. The toner collected is attracted and conveyed by the magnetic roller and is conveyed to the back side of the cleaning device.

The toner conveyed to the magnetic roller 4 is stored in a toner reservoir B formed by the roller and a toner layer thickness regulating roller 5 arranged at an appropriate distance 1ia (p>a) from the magnetic roller, and the toner is A portion of the magnetic brush stands on the surface of the magnet roller to form a magnetic brush, and as the roller rotates, it sequentially reaches a position facing the photoreceptor 1 to perform a rubbing cleaning action.

The toner overflowing from the toner reservoir B is further guided to the back side, and is discharged to the outside of the cleaning device by a conveying screw 6 as necessary. The regulating roller 5 is made of a non-magnetic material and has a surface The roller 5 is coated with a fluororesin having a thickness of approximately 10 to 50 μm, and a brush 7 disposed at an appropriate location scrubs and cleans the surface of the roller. It is possible to effectively prevent other foreign substances from adhering.

In addition to such a configuration, in the illustrated apparatus, the regulating roller 5 is arranged at its center and both ends, as shown in FIG. The diameters are different between the sections, and the gap d1 at both ends is smaller than the gap d.

With this configuration, it is possible to suppress the formation of spikes of toner at both ends of the regulating roller 5 and prevent the toner from escaping from these portions.

In the apparatus shown in FIG. 1, as shown by the arrow, when the photoreceptor l and the regulating roller 5 are facing each other, they are moved in opposite directions (
counter direction), and the regulating roller 5
By coating the fluororesin on the
The structure can be simplified by omitting the scraper of the regulating roller as shown in the figure.

For example, Teflon (trade name) is suitable for this coating, but it is not limited thereto, and any bonding substance with low surface energy can be used.

Also, set the rotation direction of the regulation roller in the opposite direction (forward direction) to the above.
In this case, in the case of the above-mentioned known device, if a large amount of toner exceeds the regulation roller for some reason, it will be attracted to the magnetic roller and transported to a position facing the photoreceptor, causing the brush to stop moving. In addition, it was necessary to run the regulation roller at a speed higher than a certain speed in order to prevent clogging with foreign matter such as paper dust mixed in the toner. By coating with a small substance, there is less adhesion of toner even when it is rotated slowly in the forward direction, and just by rubbing with the brush as described above, it is possible to prevent toner from adhering to the regulation roller and to the area facing the photoreceptor. It is possible to avoid instability in the cleaning action due to transportation.

(3) As described in detail, according to the present invention, in a cleaning device provided with a cleaning blade and a magnetic roller in an image forming apparatus, the surface of a regulating roller that regulates the toner layer thickness of the cleaning roller. The regulating roller is made of a substance with low surface energy, and the diameter of the portions near both ends of the regulating roller is increased to prevent the formation of a toner layer in these portions, so that the regulating roller is always stably kept in a predetermined position. It is possible to form a thick toner layer, and it is possible to perform good cleaning, and prevent toner from escaping from both ends of the regulation roller, thereby preventing toner contamination inside the image forming device due to toner scattering. This greatly contributes to obtaining high-quality images.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a cleaning device according to the present invention, FIG. 2 is a plan view showing the relationship between the photoreceptor and the regulating roller, and FIG. 3 is a side sectional view of a known cleaning device. ■...Photoreceptor, 2...Cleaning device, 3...
Cleaning blade, 4... Magnet roller, 5
...Toner layer thickness regulation roller, 6. Conveyance screw funeral diagram unmarked

Claims (2)

[Claims] (1) An image bearing member and a cleaning device disposed close to the image carrier and moving relative to the image carrier, the cleaning device includes a cleaning blade, and a toner layer formed of collected toner is formed on the upstream side of the cleaning blade. A magnetic roller for cleaning is disposed, and the distance between the roller for regulating the thickness of the toner layer and the image carrier is made larger at the center of the roller and smaller at both ends, and the surface of the roller is reduced by surface energy. A cleaning device made of a small substance. (2) The cleaning device according to claim 1, wherein the toner layer thickness regulating roller runs in the forward direction of the magnet roller.